1. Field of the Invention
The present invention is directed to glass reinforced blend of aromatic polycarbonate resin and acrylonitrile-butadiene-styrene graft copolymers which contain uniformly dispersed therein finely divided fibrous glass which contains a particular coating agent thereon, and more particularly relates to such compositions wherein the coating agent comprise a polyolefin wax and with a optionally functionalized silane binding agent.
2. Description of the Related Art
Fibrous glass, when incorporated with a thermoplastic polymer, beneficially aids the mechanical properties of the polymer which results in greater application thereof. In the manufacture of the fibrous glass, filaments are first formed through the use of various processes. The filaments are then gathered into a bundle known as a strand. In order to bind the filaments into a strand so that the strand can be handled, a binder or binding agent is applied to the glass filaments. Subsequently, the strand can be chopped into various lengths as desired. These are called chopped strands. Some of these binding agents are polymers such as polyvinyl acetate, particular polyester resins, starch, acrylic resins, melamine, polyvinyl chloride, polyethylene oxide, polyurethane, polyepoxide, or polyvinyl alcohol. In the particular area of thermoplastic aromatic polycarbonate resins, the fibrous glass enhances some of the mechanical properties of the polycarbonate resin. Unfortunately, in such polycarbonate resin compositions, the addition of such glasses can substantially lower the room temperature Notched Izod impact strengths of the fiber reinforced compositions, and it can also substantially reduce the biaxial impact (instrument impact) energies of such compositions. Glass fibers employing a non-bonding olefinic sizing agent which does not chemically bond with the polycarbonate resin have been previously employed in fiber reinforced polycarbonate resin compositions and have resulted in improved notched Izod impact strengths thereof compared to other glass filled polycarbonate compositions. Utilization of such glasses in blends of polycarbonate with other resins would not be expected to show such improvements due to the likelihood of the glass bonding with the non-polycarbonate resinous components of the blend compositions.
Polymer blends containing an aromatic polycarbonate resin, and rubber modified graft copolymer, such as a acrylonitrile-butadiene styrene (ABS) graft copolymer, a styrene acrylonitrile copolymer (SAN) and glass fiber reinforcements have in the past typically shown greater likelihoods of brittle failure and substantial decreases in properties such as notched Izod impact strength and biaxial impact strength compared to non-glass filled blends of such materials.
Accordingly, there is a need to provide glass reinforced polycarbonate/acrylonitrile-butadiene-styrene graft copolymer blends exhibiting enhanced properties such as Izod impact strength, biaxial impact energy, ductility, tensile and flexural properties compared to blends containing common glass reinforcement grades.